Whey Protein Supplementation Positively Modulates Lung Function and Pulmonary and Systemic Immune Response in Older Adults: A Randomized Controlled Clinical Trial

PURPOSE: Aging is associated with reduced protein intake, increasing the risk of infections by damping the pulmonary and systemic immune response. Although whey protein supplementation improves systemic immune response, its effects on the pulmonary immune response are unknown. METHODS: This clinical trial composed by two groups (Control; n = 38; Age 69.31 ± 6.13; Men = 9; Women = 27) and (Whey; n = 27;; Age 68.14 ± 5.72; Men = 12; Women = 31) investigated whether isolated whey protein supplementation (IWPS) (25 g/day; 7 days/week; 3 months) could impact the pulmonary immune response, as a primary outcome, and the lung function, systemic cellular and humoral immune response, respiratory muscle strength, functional capacity, peripheral muscle strength and body composition as secondary outcomes. RESULTS: Three months of IWPS improved the lung function, such as force expiratory volume (FEV₁) (p < 0.048), forced expiratory volume in the first second/forced vital capacity ratio (FEV₁/FVC) (forced vital capacity) (p < 0.003), forced expiratory volume 25-75% (FEF25-75%) (p < 0.048), and peak expiratory flow (PEF) (p < 0.002). IWPS reduced the fractional exhaled nitric oxide (FeNO) (p < 0.015), interleukin 6 (IL-6) (p < 0.001) and tumoral necrosis factor alpha (TNF-α) (p < 0.001) levels, while increased IL-10 (p < 0.001) and Klotho (p < 0.013) in breath condensate, displaying an anti-inflammatory and anti-aging effect. Furthermore, IWPS improved systemic immune response, as showed by reduction on blood total leukocytes (p < 0.017), neutrophils (p < 0.049), and eosinophils (p < 0.009), and plasma levels of pro-inflammatory IL-6 (p < 0.005) and TNF-α (p < 0.001) and increased levels of anti-inflammatory IL-10 (p < 0.00005) and anti-aging protein Klotho (p < 0.0436). The functional capacity (p < 0.0031), expiratory muscle (p < 0.0001) and peripheral muscle strength (p < 0.0028) was improved by IWPS. CONCLUSION: IWPS improved pulmonary and systemic immune response, lung function and functional capacity of older adults.